Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A control device comprising: a processor configured to: control calibration of sensing values in a sensor node group formed of sensor nodes each including a sensor and a wireless device and being capable of performing multi-hop communication; divide the sensor node group into a plurality of clusters such that each of the clusters includes at least one partial cluster including a relay node and a child node that performs wireless communication; collect an average of sensing values in each of the partial clusters from the relay node of each of the partial clusters; calculate a calibration reference value of each of the clusters from the collected averages of the respective partial clusters; and provide the calculated calibration reference value of each of the clusters to each of the clusters, wherein the partial cluster is a group formed of the relay node and the child node of the relay node, and in the partial cluster, the number of the child node that is accepted is limited.
This invention relates to a control device for managing and calibrating sensor networks, particularly in multi-hop wireless sensor node groups. The problem addressed is ensuring accurate and consistent sensing data across distributed sensor nodes, which can be affected by environmental factors and individual sensor variations. The control device uses a processor to perform several key functions. First, it controls the calibration of sensing values from a group of sensor nodes, each equipped with a sensor and a wireless communication device, and capable of multi-hop communication. The sensor node group is divided into multiple clusters, with each cluster containing at least one partial cluster. Each partial cluster consists of a relay node and one or more child nodes that communicate wirelessly. The number of child nodes in a partial cluster is limited to maintain communication efficiency. The control device collects the average sensing values from each partial cluster via the relay nodes. It then calculates a calibration reference value for each cluster based on the averages from the partial clusters within it. Finally, the device provides these calibration reference values to the respective clusters, ensuring that all sensor nodes within a cluster are calibrated consistently. This approach improves data accuracy and reliability in large-scale sensor networks by leveraging hierarchical clustering and localized calibration.
2. The control device according to claim 1 , wherein when a first cluster includes a plurality of partial clusters, the processor is further configured to calculate a calibration reference value of the first cluster by obtaining a weighted average based on a plurality of averages corresponding to the respective partial clusters and the number of sensor nodes included in each of the partial clusters.
This invention relates to a control device for sensor networks, specifically addressing the challenge of accurately calibrating sensor data in distributed systems where sensors may be grouped into clusters. The device includes a processor that processes sensor data from multiple sensor nodes organized into clusters. When a cluster (referred to as the first cluster) contains multiple sub-clusters (partial clusters), the processor calculates a calibration reference value for the first cluster by computing a weighted average. This weighted average is derived from the individual averages of each partial cluster, weighted by the number of sensor nodes in each partial cluster. This approach ensures that larger sub-clusters contribute more significantly to the overall calibration, improving accuracy in sensor data normalization. The method helps mitigate errors caused by variations in sensor performance or environmental factors, particularly in large-scale or hierarchical sensor networks. The invention is useful in applications requiring precise sensor calibration, such as industrial monitoring, environmental sensing, or smart infrastructure systems.
3. The control device according to claim 1 , wherein the processor is further configured to: collect sensing values of the respective sensor nodes included in each of the partial clusters; and when an outlier is included in the sensing values collected for a first cluster, calculate a calibration reference value of the first cluster while excluding a sensing value corresponding to the outlier.
This invention relates to a control device for managing sensor networks, particularly addressing the challenge of maintaining accurate data collection in the presence of outliers or faulty sensor readings. The device includes a processor that organizes sensor nodes into multiple partial clusters, each containing a subset of the nodes. The processor collects sensing values from each cluster and identifies outliers within the data. When an outlier is detected in a first cluster, the processor calculates a calibration reference value for that cluster while excluding the outlier's sensing value. This ensures that the calibration process is not skewed by erroneous or anomalous readings, improving the overall reliability of the sensor network. The device may also include a communication interface for transmitting and receiving data between the processor and the sensor nodes, as well as a memory for storing calibration data and other relevant information. The system is designed to enhance data accuracy in distributed sensing applications, such as environmental monitoring, industrial automation, or smart infrastructure, by dynamically adjusting calibration parameters to account for sensor inconsistencies.
4. The control device according to claim 3 , wherein the processor is further configured to cause a first sensor node corresponding to the outlier not to transmit a sensing value of the first sensor node but to shift to a mode to transfer the sensing value of the first sensor node.
This invention relates to a control device for managing sensor networks, particularly addressing the issue of outlier detection and data transmission efficiency. The device includes a processor that identifies outlier sensor nodes within a network, where an outlier is defined as a sensor node whose sensing values deviate significantly from expected or neighboring node values. Upon detecting an outlier, the processor configures the outlier node to stop transmitting its own sensing values directly. Instead, the outlier node shifts to a relay mode, where it forwards its sensing data to another sensor node for subsequent transmission. This approach reduces redundant data transmission, conserves energy, and improves network reliability by mitigating the impact of anomalous sensor readings. The processor may also analyze historical or neighboring node data to determine the outlier status, ensuring accurate identification before altering the node's operation. The system is particularly useful in large-scale sensor networks where energy efficiency and data integrity are critical, such as in environmental monitoring or industrial automation.
5. A non-transitory computer-readable recording medium storing a control program that causes a computer to execute a process comprising: controlling calibration of sensing values in a sensor node group formed of sensor nodes each including a sensor and a wireless device and being capable of performing multi-hop communication; dividing the sensor node group into a plurality of clusters such that each of the clusters includes at least one partial cluster including a relay node and a child node that performs wireless communication; collecting an average of sensing values in each of the partial clusters from the relay node of each of the partial clusters; calculating a calibration reference value of each of the clusters from the collected averages of the respective partial clusters; and providing the calculated calibration reference value of each of the clusters to each of the clusters, wherein the partial cluster is a group formed of the relay node and the child node of the relay node, and in the partial cluster, the number of the child node that is accepted is limited.
This invention relates to a wireless sensor network system for calibrating sensor data in a multi-hop communication environment. The system addresses the challenge of ensuring accurate and consistent sensor readings across distributed sensor nodes, which may experience variations due to environmental factors or hardware differences. The solution involves organizing sensor nodes into clusters, where each cluster contains multiple partial clusters. Each partial cluster consists of a relay node and one or more child nodes that communicate wirelessly. The number of child nodes per relay node is limited to maintain communication efficiency. The system calibrates sensor values by collecting average readings from each partial cluster via the relay nodes, then calculating a calibration reference value for each full cluster based on these averages. This reference value is distributed back to the nodes within the cluster to standardize their measurements. The approach improves data accuracy in large-scale sensor networks by leveraging hierarchical clustering and multi-hop communication to propagate calibration adjustments efficiently.
6. A sensor node that includes a sensor and a wireless device and that is capable of performing multi-hop communication, the sensor node comprising: a processor configured to: upon receiving an instruction signal for switching to a parent node mode, receive a beacon transmitted from another sensor node located near the subject node, accept the node serving as a transmission source of the received beacon as a child node of the subject node, and transmit a first instruction signal for transmission of a sensing value to the child node; upon receiving the sensing value from the child node in accordance with the first instruction signal for transmission, calculate an average of sensing values of a partial cluster including the subject node and the child node by obtaining an average of a sensing value of the subject node and the sensing value of the child node, transmit the calculated average of the sensing values to a control device through the multi-hop communication, and transmit the instruction signal for switching to the parent node mode to the child node; and upon receiving a second instruction signal for transmission of a sensing value, transmit the sensing value of the subject node to a node serving as a transmission source of the second instruction signal for transmission, wherein the partial cluster is a group formed of a relay node and the child node of the relay node, and in the partial cluster, the number of the child node that is accepted is limited.
This invention relates to a wireless sensor network system where sensor nodes perform multi-hop communication to transmit sensing data to a control device. The problem addressed is efficient data aggregation and transmission in a hierarchical network where nodes dynamically switch between parent and child roles to optimize energy consumption and network reliability. The sensor node includes a sensor, a wireless device, and a processor. When instructed to switch to a parent node mode, the node receives a beacon from a nearby sensor node, accepts that node as a child, and sends an instruction to the child to transmit its sensing value. Upon receiving the child's sensing value, the parent calculates an average of the sensing values from both nodes (forming a partial cluster) and transmits this average to the control device via multi-hop communication. The parent then instructs the child to switch to parent mode. If the node receives a transmission instruction from another node, it sends its own sensing value to that node. The partial cluster consists of a relay node and its child, with the number of child nodes limited to maintain network efficiency. This dynamic role-switching and data aggregation reduce redundant transmissions and energy usage in the network.
7. The sensor node according to claim 6 , wherein upon receiving a calibration reference value of a cluster including the subject node, the processor is further configured to correct the sensing value of the subject node by using the calibration reference value.
A sensor node is configured to operate within a wireless sensor network, where multiple nodes collaborate to monitor environmental conditions. The problem addressed is ensuring accurate and consistent measurements across distributed nodes, which can be affected by individual sensor drift or environmental variations. The sensor node includes a processor that receives a calibration reference value from a cluster of nodes, which includes the subject node. Upon receiving this reference value, the processor corrects the sensing value of the subject node by applying the calibration reference value. This correction compensates for discrepancies in measurements, improving overall accuracy. The calibration reference value may be derived from aggregated data or a designated reference node within the cluster, ensuring that all nodes in the network maintain synchronized and reliable measurements. This approach reduces the need for individual node calibration, simplifying maintenance and enhancing system efficiency. The sensor node may also include communication circuitry for transmitting and receiving data within the network, and a sensing unit for detecting environmental parameters such as temperature, humidity, or pressure. The processor further processes the corrected sensing values for transmission or local storage, enabling real-time monitoring and data analysis. This system is particularly useful in industrial, environmental, or smart infrastructure applications where precise and consistent sensor data is critical.
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December 24, 2019
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